Vulnerability Description
jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. Prior to 4.5.7, JupyterLab's HTML sanitizer allowlists data-commandlinker-command and data-commandlinker-args on button elements, while CommandLinker listens for all click events on document.body and executes the named command without checking whether the element came from trusted JupyterLab UI. A notebook with a pre-saved HTML cell output containing a deceptive button can trigger arbitrary JupyterLab commands - including arbitrary code execution - on a single user click, without any code being submitted for execution by the user. This vulnerability is fixed in 4.5.7.
Related Weaknesses (CWE)
References
FAQ
What is CVE-2026-42557?
CVE-2026-42557 is a documented vulnerability. jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. Prior to 4.5.7, JupyterLab's HTML sanitizer allowlists data-commandlinke...
How severe is CVE-2026-42557?
CVSS scoring is not yet available for CVE-2026-42557. Check NVD for updates.
Is there a patch for CVE-2026-42557?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.